<!-- Définition de la zone de navigation -->
<div id="zone_navigation">
    <a id="btn_home" type="button" href="<?php echo site_url('home/index'); ?>">
        <div class="btns_navigation">
            <img id="img_btn_home" height="50" width="53" src="<?php echo(img_commun_url('commun_btn_home.png'));?>"> 
        </div>
    </a>

    <!-- Si $previous_chapter>=0 -->
    <?php if($previous_chapter>=0){?>
        <a id="btn_previous_chapters" type="button" onclick="goToChapters('<?php echo $previous_chapter;?>')">
            <div class="btns_navigation">
                <img id="img_btn_previous" height="50" width="53" src="<?php echo(img_commun_url('commun_btn_previous.png'));?>"> 
            </div>
        </a>
        <!-- Si $previous_chapter<=3 -->
        <?php if($previous_chapter<3){?>
        <a id="btn_next_chapters" type="button" onclick="goToChapters('<?php echo $next_chapter;?>')">
        <div class="btns_navigation">
            <img id="img_btn_next" height="50" width="53" src="<?php echo(img_commun_url('commun_btn_next.png'));?>"> 
        </div>
        </a>
    <?php }
    }
    else{?>
    <!-- Si $previous_chapter<=3 -->
        <?php if($previous_chapter<3){?>
        <a id="btn_next_intro" type="button" onclick="goToChapters('<?php echo $next_chapter;?>')">
        <div class="btns_navigation">
            <img id="img_btn_next" height="50" width="53" src="<?php echo(img_commun_url('commun_btn_next.png'));?>"> 
        </div>
        </a>
    <?php }
    }?>
</div>
